I can certainly agree that my approach to writing a game design out vs. writing a short-story or novel are completely different, but that mostly rests in how I'll present the material -- for a novel I'll be, well, writing a novel but when I approach a game, I break it down into its core elements and make lots of lists; I'm often tempted to write about the game as if it were a story which is a habit I'm still trying to curb. As far as content goes, no I don't think my approaches differ too strongly; I try not to 'target' an audience and simply attempt to produce an experience that I want to share with others, one that I think will touch a variety of viewers. I think that can work for games and normal fiction.

Also, people tend to work on what interests them -- so just because you don't see anyone else trying to construct a romantic simulation, doesn't necessarily mean that others couldn't jive with that type of game. I can only work on projects that interest me or else I become bored quite easily. It also depends on how you approach a game-type. Rather than putting gender labels on games, find a way to make them appeal to a wider audience. I think Fable's inclusion of the whole sexual reproduction/family system gave some players a chance to participate in a certain type of gameplay that they wouldn't have, were it standalone -- it presented the aspect in an RPG, fantasy setting that seems to appeal to a wide audience. With that said, I don't see why we can't create games that compromise and present the player with uncommon activities that are presented in a familiar way.

I think for the most part, games are designed to satisfy a target audience and by that very process, they're obviously going to exclude some audiences. I can see creating games to fill a vacant niche market if you're really focused on creating something marketable, or trying to make something that can satsify a niche that has gone unattended. I hear a lot about "hardcore" and "casual" gamers now a days and that tends to break games into either FPS or family-friendly pickup games; there are of course other games that try to appeal to players who love a game with stories, or thought-provoking gameplay, but these games (at least in my opinion) almost supercede the hardcore/casual label since you could easily find people in either category who are more interested in experiencing a story as opposed to simple fire-fights or party games.

I think if you, or anyone, has a really interesting idea -- even if there doesn't seem like there would be an obvious market for it -- to just follow through with it and see what happens. People will buy almost anything and it's hard to accept that something can't have a target audience; they're out there, you just have to lure them out with something new.

As far as what I think, I believe that it is possible to have a non-humanoid act as a protagonist -- or even antagonist. The writer simply has to present the object/character in such a way that the player will want to invest their time into the story and gameplay. Most games have an endgame. Player starts here --> ends here. Even if it was a pixel entering a fractal, to save other pixels, I get a sense of adventure and heroism. Who is this tiny pixel, and why does he think he can save the other pixels? Other things like art and gameplay can really help to sell the unusual protagonist as well.

Not quite a character, but the game "Flower" has you controlling a single flower petal (inside of a plant's dream) and you guide it around beautiful landscapes, rousing other plants to bloom and collecting other flora to accompany your single petal. Obviously the petal isn't a protagonist in any sense, but it's what the player controls and they have to invest themselves in the notion that they are going to experience something unique through controlling this object. I haven't played the game myself, however I don't think it follows a single plot -- it's more like an experience.

But by that same company is a game called "Journey." It has a subtle focus, but the character is completely anonymous -- who knows what lurks behind the shadow of its hood? I think anonymity could be put into the non-humanoid category because for all you know, you could be playing as a Dog/Broom wearing a cloak, manipulated by forces unseen; but it's the combination of these things that creates the character and protagonist, and this scenario could possibly work out incredibly well given a good enough explanation. I think once you identify the possibe motives of this 'object', it sort of inherently acquires traits we usually reserve for sentient things. Heck, you could probably turn the number "1" into a protagonist, sent on a journey to acquire the greatness of a triple digit and it must encounter other numbers to learn the ways of yadda, yadda, yadda.